Heavy duty switch having spaced contact assemblies



s. A. WOOD 3,165,613

HEAVY nun swnca mwmc SPACED CONTACT ASSEMBLIES Jan. 12, 1965 2 Sheets-Sheet 1 Filed April 16, 1962 mvmox aver/1 afl 14 0 00 zuqw ATTORNEYS Jan. 12, 1965 s. A. WOOD 3,165,613

HEAVY mm swrrca HAVING SPACED CONTACT ASSEMBLIES I Filed April 16, 1962 2 sheets-sign 2 INVENTOR. 6 /92/754 .0 A h/ooa O ZMM United States Patent Filed Apr. 16, 1962, Ser. No. 187,473 4 Claims. (Cl. 200-163) The present invention relates to heavy duty electric switches, and particularly to aheavy duty electric switch having a plurality of contact plate assemblies progressively engaged by a sliding contact bar.

It is one object of the invention to provide an electric switch that can carry large currents with minimum arcing between contacts.

It is another object of the invention to provide a heavy duty electric switch having a plurality of spaced contact assemblies which are progressively engaged by a sliding contact bar, the contact bar maintaining engagement with each of the contact assemblies as it progressively slides from one contact to the other. 1

It is a further object of the invention to provide a heavy duty electric switch of the type described above wherein the contact assemblies comprise fiat, parallel spaced apart contact plates, at least one of which is resiliently biased toward the other to ensure a good area contact with opposed flat surfaces of the sliding contact bar.

It is a still further object of the invention to provide a heavy duy electric switch of the type described above wherein one of the contact plates of each pair of contact plates is fixed to an insulated base on which the contact bar is slidably mounted and the other contact plate of each pair is floatingly positioned above and resiliently biased toward the fixed plate so as to be normally spaced therefrom a distance slightly less than the thickness of the contact bar.

It is a still further object of the invention to provide a heavy duty electric switch which is economical to manufacture, rugged in construction and reliable and effective 1n use. 7

Other objects and features of novelty of the present invention will bespecifically pointed out or will otherwise become apparent when referring, for a better understanding of the invention, to the following description taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a plan view of an electric switch embodying features of the invention;

FIG. 2 is a sectional view taken on the line 22 of FIG. 1;

FIG. 3 is a side view of the switch illustrated in FIG. 1;

FIG. 4 is a perspective View of an actuating mechanism mounted next to the seat of an electric vehicle and connected to the handle of the switch illustrated in FIG. 1 for actuating the switch; and

FIG. 5 is a plan view of the actuating mechanism illustrated in FIG. 4.

Referring to FIGS. 1-3, an electric switch embodying features of the present invention is illustrated which comprises a base 12 made of a suitable insulating material and having a flat elongated contact bar 14 slidably mounted thereabove by guide plate assemblies 16 and 18. Each of the guide plate assemblies comprises a pair of parallel plates 20 and 22 spaced apart by a pair of spacers 24 positioned between the ends thereof. The plates 20 and 22 and spacers 24 are firmly secured to the base 12 by bolts 26 extending therethrough and threadably engaging the base 12, a washer 28 being preferably positioned between the head of the bolt and the plate 22. The inner edges of each of the four spacers 24 slidably engage the edges of the contact bar 14 so as to cooperate with the plates 20 and 22 to accurately guide the sliding movement of the contact bar.

A suitable handle 30 is secured to the contact bar 14 by a bolt 32 threadably engaging the contact bar with a suitable spacer 34 provided to space the right end 36 of the handle above the contact bar 14 a sufiicient distance to clear the guide plate assembly 18 when in the position illustrated in FIG. 1. With this construction, the contact bar can be moved from the position illustrated in FIGS. 1 and 3 to the right until the spacer 34 abuts against the spacers 24 of the guide plate assembly 16. If desired, the left end of the handle 30 may be turned relative to the remainder of the handle and a slot 38 provided therein to enable the handle to be pinned to the pivoting end of a suitable actuating lever by a pin and slot connection. In this manner the contact bar 14 can be shifted back and forth in response to the pivoting movement of the actuating lever with the pin and slot connection providing the necessary lost motion therebetween, as will be described in greater detail hereinafter.

A plurality of spaced contact assemblies 40-46 are mounted on the base 12 in alignment with the contact bar 14. Each of the contact assemblies comprises a contact plate 48 positioned on the base 12 perpendicular to the contact bar 14 with one end thereof extending beyond the side of the base. The extended end of each contact plate 48 has an aperture 51 therein to provide a terminal for making electrical connection to the contact plate. A shorter contact plate 52 is supported above the contact plate 48 by bushings or rollers 54 and 56, and all of these elements are secured to the base 12 by bolts 5'3 and 6%) having nuts 62 on the threaded upper ends thereof.

The nuts 62 and washers 64 therebeneath are spaced above the upper contact plate 52 to enable a suitable concave leaf spring 66 to be positioned over the upper contact plate 52 with the ends thereof secured beneath the washers 64 by the bolts 58- and 60 and the center thereof pressed against the center of the contact plate 52. With this con .struction, the upper contact plate is normally resiliently biased to the position illustrated in FIG. 2 by the leaf spring 66 and in this position is spaced from the lower contact plate 48 a distance slightly less than the thickness of the contact bar 14. Consequently, as the contact bar 14 slides progressively between each pair of contact plates, it will raise the upper contact plate 52 against the resistance of the leaf spring 66, which can be varied by adjusting the nuts 62. By providing a loose fit between the contact plate 52 and the bolts 58 and 60, the contact plate can float or cock slightly relative to the bolts to ensure a good, flat surface engagement with the fiat upper surface of the contact bar. The contact plates 48 and 52 are electrically interconnected by a flexible jumper or wire 68 to make certain there is a good electrical connection between the contact plates at all times. To assist the end of the contact bar 14 in moving between the contact plates of each contact assembly, the front edges of the bar may be bevelled or the entire end rounded, as illustrated in FIG. 3.

With this construction, separate electrical leads can be connected to each of the terminals on the projecting end of the lower contact plates48 and a flexible lead can be connected to the trailing end of the contact bar 14 by means of an aperture '75 provided therein. Consequently when the contact bar 14 is shifted to the right from the position illustrated in FIGS. 1 and 3 through each of the contact assemblies 4tl46, it will progressively close the circuit between the flexible lead connected to the terminal on the trailing end of the contact bar and each of the leads connected to the terminals on the projecting ends of the lower contact plates 48.

A good example of an application for the electric switch 10 is illustrated in my copending application Serial Number 175,963, filed on February 27, 1962, now abandoned, which discloses an electric control device for controlling Q t3 the speed of a DC. motor for driving a battery-powered electric vehicle. In this application, the vehicle is op ated at a first low speed by connecting a first resistance coil in series with the DC. motor, a second higher speed by adding a second resistance coil in parallel with the first resistance coil to decrease the total resistance in series with the D.C. motor, a third higherspeed by adding a third resistance coil in parallel with the first two resistance coils, and a fourth final high speed by adding a shunt line in parallel with the three resistance coils. In utilizing the electric switch W for this application, the trailing end of the contact bar 14 may be connected to the grounded terminal of the batteries andweach of the terminals on the contact assemblies 449-46 connected to the first, second and :third resistance coils and the shunt line, respectively. Therefore when the contactbar is shifted to the right between the contact plates of the contact assembly 41), the first resistance coil will be connected in series with the DC. motor of the vehicle. When it is shifted further to the right between the contact plates of the contact assembly 42, the second resistance coil will be connected in parallel with the first resistance coil since the contact bar does not disengage the contact assembly do, Similarly the third resistance coil is connected in the circuit when the contact bar moves between the contact plates of the contact assembly 24 and the shunt line connected in the circuit when the contact bar moves between the contact plates of the contact assembly as. By making the electrical connection with each succeeding contact assembly while maintaining the electrical connection with the previously engaged contact assemblies, the arcing between the contact bar 14 and the contact assembly which is being approched is eifectively held to a minimum.

As mentioned above, the end of the handle 30is provided with a slot 3% to facilitate connection to a lever for shifting the contact bar 14 back and forth. This actuating mechanism is shown in FIGS. 4 and 5 mounted next to the seat 7 ll of an electric vehicle such as the three-wheeled Post Oifice vehicle disclosed in my aforementioned application. It comprises an upright support member 72 fixed in position to support a lever 74 pivotally connected'thereto by a bolt 76. The lower end of the lever 74 is pivotally connected to the handle 3% of the switch Ill (the remainder of the switch not being shown) by a bolt '78 passing through the slot 33 to provide the necessary lost motion therebetween.

A downwardly presenting U-shaped member 8% is fitted over the upper end of the lever 74 next to an arcuate segmental element 82 mounted on the support member '72 and having a curved edge 84. .A handle 36 is bolted to the upper end of the lever '74 by a bolt 88 and pinned to the U-shaped member 86) by a pin 99. A finger 92 is pivotally secured to the other end of the pin 9%? and slidably engages the curved edge 84 to cooperate with notches 94 therein to releasably position the, contactba-r 14 in the various 'dilferent positions previously described. Suitable spring means (not shown) is provided for resiliently biasing the finger 92 so that a projection on the right end thereof snaps into each notch 94 as it slides. over the curved edge 84.

While it will be apparent that the embodiment of the invention herein disclosed is well calculated to fulfill the objects of the invention, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoinedclaims.

What is claimed is:

1. An electric switch comprising an insulated base, an elongated fiat contact bar slidably mounted on said base, a plurality of spaced contact plates mounted on said base and extending substantially perpendicular to the line of movement of said contact bar in position to be progressively slidably engaged by said contact bar, a plurality of second contact plates, means for resiliently and fioatingly supporting each of said second contact plates in parallel spaced relation above one of said fixed contact plates with the spacing between each pair of contact plates normally being less than the thickness of said contact bar, and means for electrically interconnecting each pair of contact plates whereby said flat contact bar can progressively slide between each pair of contact plates to close a circuit therewith with each of the floating plates rfirmly resiliently biased against a fiat surface of said contact bar to ensure good area engagement therewith,

2. An electric switch comprising an elongated base of insulating material, an elongated -flat contact bar, guide means for slidably mounting said contact bar on said base, a plurality of spaced contact plates mounted on said base substantially perpendicular to the line of movement of said contact bar in position to be progressively slidably engaged by a fiat bottom surface of said contact bar, a pair of spaced bushings supported on each of said contact plates, a second contact plate supported on each pair of bushings in parallel spaced relation with the first mentioned contact plate associated therewith, a plurality of bolts extending upwardly through said base and each of said bushings and the contact plates associated therewith, a concave leaf spring positioned above eachof said second contact plates with'the ends thereof fitted over said bolts and the center thereof resting on the second contact plate associated therewith, a nut threaded on each of said bolts over the ends of the leaf springs to secure the contact plates together with the leaf springs normally resiliently biasing the second contact plates associated therewith against the bushings, the height of said bushings being less than the thickness of said fiat contact bar whereby said flat contact bar can progressively slide bet-ween each pair of contact plates to close a circuit therewith with each of said second contact plates firmly resiliently biased against the fiat upper surface of said contact bar to ensure good area contact therewith, and the pressure exerted by said leaf springs can be varied by adjusting said nuts.

3. The invention as defined in claim 2 wherein one end of each of said firstmentioned contact plates projects beyond the edge of saidbase to facilitate electrical connec- .tion therewith, and including a plurality of flexible leads electrically interconnecting each pair of contact plates.

4. An electric switch comprising an insulated base, a fiat contact bar slidably mounted on said base, a plurality of spaced contact means mounted on said base in alignment with said contact bar, each of said contact means comprising a pair of spaced contact plates extending substantially perpendicular to the line-of movement of said contact bar, and means for normally positioning said contact plates spaced a predetermined distance from one another .and resiliently biasing at least one of said. contact plates of each pair of contactplates toward said normal position, said contact bar being progressively slidable between each pair of said contact plates, said predetermined distance. being less than the thickness of said flat contact bar whereby the contact .bar will spread the contact plates as it passes therebetween, a handle secured to said contact bar, fixed-support means having an arcuate segmental element thereon with a curved edge, a lever pivotally mounted onsaid support means with one end thereof pivotally connected to said handle, and a resiliently biased finger connected to said lever means and slidably engaging said curved edge, said curved edge having a plurality of notches therein which cooperate with said resiliently biased finger to releasably position said contact bar in a plurality of different positions.

References (Jited in the file of this patent UNITED STATES PATENTS 722,453 Murphy Mar. 10, 1903 2,999,912 Kincaid et al Sept. 12, 1961 

1. AN ELECTRIC SWITCH COMPRISING AN INSULATED BASE, AN ELONGATED FLAT CONTACT BAR SLIDABLY MOUNTED ON SAID BASE, A PLURALITY OF SPACED CONTACT PLATES MOUNTED ON SAID BASE AND EXTENDING SUBSTANTIALLY PERPENDICULAR TO THE LINE OF MOVEMENT OF SAID CONTACT BAR IN POSITION TO BE PROGRESSIVELY SLIDABLY ENGAGED BY SAID CONTACT BAR, A PLURALITY OF SECOND CONTACT PLATES, MEANS FOR RESILIENTLY AND FLOATINGLY SUPPORTING EACH OF SAID SECOND CONTACT PLATES IN PARALLEL SPACED RELATION ABOVE ONE OF SAID FIXED CONTACT PLATES WITH THE SPACING BETWEEN EACH PAIR OF CONTACT PLATES NORMALLY BEING LESS THAN THE THICKNESS OF SAID CONTACT BAR, AND MEANS FOR ELECTRICALLY INTERCONNECTING EACH PAIR OF CONTACT PLATES WHEREBY SAID FLAT CONTACT BAR CAN PROGRESSIVELY SLIDE BETWEEN EACH PAIR OF CONTACT PLATES TO CLOSE A CIRCUIT THEREWITH WITH EACH OF THE FLOATING PLATES FIRMLY RESILIENTLY BIAS AGAINST A FLAT SURFACE OF SAID CONTACT BAR TO ENSURE GOOD AREA ENGAGEMENT THEREWITH. 